1/*
2 * Copyright 2012 David Chisnall. All rights reserved.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to
6 * deal in the Software without restriction, including without limitation the
7 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
8 * sell copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be
12 * included in all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
15 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
17 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
18 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
19 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
20 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21 */
22
23/**
24 * ARM-specific unwind definitions.  These are taken from the ARM EHABI
25 * specification.
26 */
27 typedef enum
28{
29	_URC_OK = 0,                /* operation completed successfully */
30	_URC_FOREIGN_EXCEPTION_CAUGHT = 1,
31	_URC_END_OF_STACK = 5,
32	_URC_HANDLER_FOUND = 6,
33	_URC_INSTALL_CONTEXT = 7,
34	_URC_CONTINUE_UNWIND = 8,
35	_URC_FAILURE = 9,            /* unspecified failure of some kind */
36	_URC_FATAL_PHASE1_ERROR = _URC_FAILURE
37} _Unwind_Reason_Code;
38
39typedef int _Unwind_Action;
40
41typedef uint32_t _Unwind_State;
42#ifdef __clang__
43static const _Unwind_State _US_VIRTUAL_UNWIND_FRAME  = 0;
44static const _Unwind_State _US_UNWIND_FRAME_STARTING = 1;
45static const _Unwind_State _US_UNWIND_FRAME_RESUME   = 2;
46static const _Unwind_State _US_ACTION_MASK           = 3;
47#else // GCC fails at knowing what a constant expression is
48#	define _US_VIRTUAL_UNWIND_FRAME  0
49#	define _US_UNWIND_FRAME_STARTING 1
50#	define _US_UNWIND_FRAME_RESUME   2
51#	define _US_ACTION_MASK           3
52#endif
53
54typedef struct _Unwind_Context _Unwind_Context;
55
56typedef uint32_t _Unwind_EHT_Header;
57
58struct _Unwind_Exception
59{
60	uint64_t exception_class;
61	void (*exception_cleanup)(_Unwind_Reason_Code, struct _Unwind_Exception *);
62	/* Unwinder cache, private fields for the unwinder's use */
63	struct
64	{
65		uint32_t reserved1;
66		uint32_t reserved2;
67		uint32_t reserved3;
68		uint32_t reserved4;
69		uint32_t reserved5;
70	/* init reserved1 to 0, then don't touch */
71	} unwinder_cache;
72	/* Propagation barrier cache (valid after phase 1): */
73	struct
74	{
75		uint32_t sp;
76		uint32_t bitpattern[5];
77	} barrier_cache;
78	/* Cleanup cache (preserved over cleanup): */
79	struct
80	{
81		uint32_t bitpattern[4];
82	} cleanup_cache;
83	/* Pr cache (for pr's benefit): */
84	struct
85	{
86		/** function start address */
87		uint32_t fnstart;
88		/** pointer to EHT entry header word */
89		_Unwind_EHT_Header *ehtp;
90		/** additional data */
91		uint32_t additional;
92		uint32_t reserved1;
93	} pr_cache;
94	/** Force alignment of next item to 8-byte boundary */
95	long long int :0;
96};
97
98/* Unwinding functions */
99_Unwind_Reason_Code _Unwind_RaiseException(struct _Unwind_Exception *ucbp);
100void _Unwind_Resume(struct _Unwind_Exception *ucbp);
101void _Unwind_Complete(struct _Unwind_Exception *ucbp);
102void _Unwind_DeleteException(struct _Unwind_Exception *ucbp);
103void *_Unwind_GetLanguageSpecificData(struct _Unwind_Context*);
104
105typedef enum
106{
107	_UVRSR_OK = 0,
108	_UVRSR_NOT_IMPLEMENTED = 1,
109	_UVRSR_FAILED = 2
110} _Unwind_VRS_Result;
111typedef enum
112{
113	_UVRSC_CORE = 0,
114	_UVRSC_VFP = 1,
115	_UVRSC_WMMXD = 3,
116	_UVRSC_WMMXC = 4
117} _Unwind_VRS_RegClass;
118typedef enum
119{
120	_UVRSD_UINT32 = 0,
121	_UVRSD_VFPX = 1,
122	_UVRSD_UINT64 = 3,
123	_UVRSD_FLOAT = 4,
124	_UVRSD_DOUBLE = 5
125} _Unwind_VRS_DataRepresentation;
126
127_Unwind_VRS_Result _Unwind_VRS_Get(_Unwind_Context *context,
128                                   _Unwind_VRS_RegClass regclass,
129                                   uint32_t regno,
130                                   _Unwind_VRS_DataRepresentation representation,
131                                   void *valuep);
132_Unwind_VRS_Result _Unwind_VRS_Set(_Unwind_Context *context,
133                                   _Unwind_VRS_RegClass regclass,
134                                   uint32_t regno,
135                                   _Unwind_VRS_DataRepresentation representation,
136                                   void *valuep);
137
138/* Return the base-address for data references.  */
139extern unsigned long _Unwind_GetDataRelBase(struct _Unwind_Context *);
140
141/* Return the base-address for text references.  */
142extern unsigned long _Unwind_GetTextRelBase(struct _Unwind_Context *);
143extern unsigned long _Unwind_GetRegionStart(struct _Unwind_Context *);
144
145typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn) (struct _Unwind_Context *,
146						 void *);
147extern _Unwind_Reason_Code _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
148extern _Unwind_Reason_Code
149	  _Unwind_Resume_or_Rethrow (struct _Unwind_Exception *);
150
151/**
152 * The next set of functions are compatibility extensions, implementing Itanium
153 * ABI functions on top of ARM ones.
154 */
155
156#define _UA_SEARCH_PHASE	1
157#define _UA_CLEANUP_PHASE	2
158#define _UA_HANDLER_FRAME	4
159#define _UA_FORCE_UNWIND	8
160
161static inline unsigned long _Unwind_GetGR(struct _Unwind_Context *context, int reg)
162{
163	unsigned long val;
164	_Unwind_VRS_Get(context, _UVRSC_CORE, reg, _UVRSD_UINT32, &val);
165	return val;
166}
167static inline  void _Unwind_SetGR(struct _Unwind_Context *context, int reg, unsigned long val)
168{
169	_Unwind_VRS_Set(context, _UVRSC_CORE, reg, _UVRSD_UINT32, &val);
170}
171static inline unsigned long _Unwind_GetIP(_Unwind_Context *context)
172{
173	// Low bit store the thumb state - discard it
174	return _Unwind_GetGR(context, 15) & ~1;
175}
176static inline void _Unwind_SetIP(_Unwind_Context *context, unsigned long val)
177{
178	// The lowest bit of the instruction pointer indicates whether we're in
179	// thumb or ARM mode.  This is assumed to be fixed throughout a function,
180	// so must be propagated when setting the program counter.
181	unsigned long thumbState = _Unwind_GetGR(context, 15) & 1;
182   _Unwind_SetGR(context, 15, (val | thumbState));
183}
184
185/** GNU API function that unwinds the frame */
186_Unwind_Reason_Code __gnu_unwind_frame(struct _Unwind_Exception*, struct _Unwind_Context*);
187
188
189#define DECLARE_PERSONALITY_FUNCTION(name) \
190_Unwind_Reason_Code name(_Unwind_State state,\
191                         struct _Unwind_Exception *exceptionObject,\
192                         struct _Unwind_Context *context);
193
194#define BEGIN_PERSONALITY_FUNCTION(name) \
195_Unwind_Reason_Code name(_Unwind_State state,\
196                         struct _Unwind_Exception *exceptionObject,\
197                         struct _Unwind_Context *context)\
198{\
199	int version = 1;\
200	uint64_t exceptionClass = exceptionObject->exception_class;\
201	int actions;\
202	switch (state)\
203	{\
204		default: return _URC_FAILURE;\
205		case _US_VIRTUAL_UNWIND_FRAME:\
206		{\
207			actions = _UA_SEARCH_PHASE;\
208			break;\
209		}\
210		case _US_UNWIND_FRAME_STARTING:\
211		{\
212			actions = _UA_CLEANUP_PHASE;\
213			if (exceptionObject->barrier_cache.sp == _Unwind_GetGR(context, 13))\
214			{\
215				actions |= _UA_HANDLER_FRAME;\
216			}\
217			break;\
218		}\
219		case _US_UNWIND_FRAME_RESUME:\
220		{\
221			return continueUnwinding(exceptionObject, context);\
222			break;\
223		}\
224	}\
225	_Unwind_SetGR (context, 12, reinterpret_cast<unsigned long>(exceptionObject));\
226
227#define CALL_PERSONALITY_FUNCTION(name) name(state,exceptionObject,context)
228